<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>网页基础样式</title>
    <!-- 内部样式表 -->
    <style>
        div {
            /* width: 100px; */
            height: 100px;
            /* background-color: blue; */
            border: 2px solid red;
        }
    </style>
</head>

<body>
    <div></div>
</body>

</html>